I have two of these OEM Lights for $5.00: http://ledshoppe.com/Product/ledp/LP3019.htm

I believe they are the OEM of the Topeak White Lights: https://shop.sunrisecyclery.com/item/11631

They're pretty bright and I can see them at least 3/4 down my neighborhood block. However, the straps are cheap and I already broke one (now taped to my fork).